Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantas semanas os Green Bay Packers tiveram como adversários?
 ###Tabelas: CREATE TABLE michigan_63_oberlin_0 (michigan_63_oberlin_0_id AUTO_INCREMENT PRIMARY KEY, Player VARCHAR, Touchdowns INT, Extra points INT, Field goals INT, Points INT) CREATE TABLE "clawhammer"_c0__&__cg_130_nm_desktop_replacement ("clawhammer"_c0__&__cg_130_nm_desktop_replacement_id AUTO_INCREMENT PRIMARY KEY, Model Number VARCHAR, Frequency VARCHAR, L2 Cache VARCHAR, HT VARCHAR, Mult. 1 VARCHAR, V Core VARCHAR, TDP VARCHAR, Socket VARCHAR, Release Date VARCHAR, Part Number(s) VARCHAR) CREATE TABLE ships_of_the_great_eastern_railway (ships_of_the_great_eastern_railway_id AUTO_INCREMENT PRIMARY KEY, Ship's name VARCHAR, Entered service VARCHAR, Ended service VARCHAR, Gross Tonnage INT, Type of Vessel VARCHAR) CREATE TABLE season_4_1997 (season_4_1997_id AUTO_INCREMENT PRIMARY KEY, No. in series VARCHAR, No. in season VARCHAR, Title VARCHAR, Directed by VARCHAR, Written by VARCHAR, Original air date VARCHAR, Production code VARCHAR) CREATE TABLE schedule (schedule_id AUTO_INCREMENT PRIMARY KEY, Week INT, Date VARCHAR, Opponent VARCHAR, Result VARCHAR, Attendance VARCHAR)  
SELECT SUM Week FROM schedule WHERE Opponent = green bay packers